Strand coating apparatus



July 6, 1943. v. A. RAYBURN STRAND COATING APPARATUS Filed April 30, 194].

nnn hn ll H 76" III-67 'L-n A Q II W FIGS INVENTOR KAJPAYBURN ATTORNEY Patented July 6, 1943 STRAND COATING APPARATUS Vincent A. Rayburn, Baltimore, Md., assignmto Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application April 30, 1941, Serial No. 391,033

8 Claims.

This invention relates to strand coating apparatus, and more particularly to apparatus for coating insulated electrical conductors with materials to improve their insulating properties and to render them weatherproof.

The application of a coating of viscous materials to strands presents various problems the solutions of which depend upon the nature of each material, the structure of the strand, the required smoothness of the coating of the material, and the maximum speed of the strand during the application of the material to form a uniform coating on the strand without bare spots or excess lumps.

An object of the invention is to provide a strand coating apparatus which is simple in structure and highly efficient in operation for applying material to a strand.

With this and other objects in view, the invention comprises a strand coating apparatus having complementary rolls with complementary grooves forming a die in interfitting portions of contours to supply a constant quantity of material to a strand passing through the die and maintain alignment of the grooves of the die.

Other objects and advantages will be apparent from the following detailed description when taken in conjunction with the accompanying drawing, wherein Y Fig. l is a side elevational view of the apparatus, a portion thereof being shown in section;

Fig. 2 is a top plan view of the apparatus, and

Fig. 3 is an enlarged fragmentary detailed view of one pair of the complementary rolls.

Referring now to the drawing, attention is directed to Figs. 1 and 2, which illustrate a tank Ill supported upon legs II which are mounted upon a suitable support such as a table I2. The tank in is substantially square in contour and is formed with suitable insulation l4 and a steam chamber IS, the latter being supplied with steam from a supply line I 6. The purpose of the steam chamber is tdheat the interior of the tank, to maintain a material I! therein in a molten condition. The material l1 may be of any suitable type but the device is constructed and particularly adaptedfor'viscous material such as asphalt, waxes, pitches etc.

A bearing block l8 ismounted in one wall of the tank It! and includes a. bearing IQ for rotatably supporting a shaft ljland a packing gland 2 l', to form a seal about the shaft. The shaft extends partially across-the. tank to above the normal upper surface of' the material l1 and has a plurality (in this instance four) of lower rolls 24 as well as a gear 25 for each roll mounted thereon in the position shown in Fig. 2. The rolls are fixed to the shaft and may be spaced desired distance from each other and accurately located in their respective positions by suitable means such as collars (not shown).- The ears 25 may either be fixed to the shaft to rotate with their respective rolls or secured directly to their rolls. As illustrated in Fig. 3 of the drawing, each lower roll has a peripheral groove 26 substantially rectangular in cross section and in the center of the bottom of this groov a concave annular recess 21 is formed.

An upper roll 28 is provided for each of the lower rolls. Each upper roll 28 has a central annular tongue portion 29 receivable in the peripheral groove 26 of its respective lower roll 24, the portions on each side of the central portion being reduced to allow intermeshing of the rolls and to allow spaces 33 between the rolls forthe escapement of excess material, should there be any, these spaces being, for example one-six teenth of an inch wide. However, no such spaces exist between the associated surfaces of the groove and tongue portion. These surfaces are closely positioned, there being a possible clearance of .002 of an inch to allow relative rotation of the rolls but no building up .or accumulation of the material thereon at these surfaces.' With this construction the rolls in each pair are maintained in accurate alignment one with the other and the annular recess 21 of each lower roll is maintained in accurate alignment with similar recess 30 of its respective upper roll even during relative movement of the rolls, that is, toward and away from each other. The annular recesses 21 and 30 cooperate to form a die adjacent the meeting lines of the two rolls in each pair during their relative rotation. The upper edges oi the groove 26 in each lower roll 24 are bevelled as at 3|, and the outer edges of the central portion 29 of each upper roll 28 are bevelled, as at 32, these contours assisting in the escapement of excess material, if there should be any, through the spaces 33. The upper roll 28 of each pair is driven in the opposite direction from that of its lower roll and at the same surface speed through the aid of a gear 34 fixed thereto and operatively connected to its respective gear 25. The intermeshing teeth of gears 34 and 35 are of the coarse type, permitting relative movement of the rolls certain distances without affecting the driving connections of the gears or the speed of rotation of the rolls. 2 ,i

The power means for rotating shaft 20 may be any suitable means such as an electric motor (not shown), connected, through a chain 40 and a sprocket wheel 4|, to shaft 42 to drive a reduction gear unit indicated at 43. The structure of the unit 43 is not shown but may be of the conventional type and include a driven shaft 44. The unit 43 is mounted upon the table |2 to position the shaft 44 parallel with the shaft 20. A sprocket wheel 46 having a clutch member 41, is freely mounted on the shaft 44 and is operatively connected to a sprocket wheel 48' through a chain 49. The sprocket wheel 48 is mounted upon and fixed to the shaft 20 between the bearing I9 and a bearing 50, the latter being supported by a bearing bracket 5| mounted upon the table I2.

Returning now to the shaft 44, a clutch member 53 is mounted upon the shaft and operatively connected for rotation with the shaft through a key or spline connection (not shown). The clutch members 41 and 53 are formed to interengage to connect and discon. .-ct the sprocket wheel 43 with the driven shaft 44. Means is provided to effect actuation of the clutch member 53. This means consists of a floating ring 55 carried in a groove of the clutch member 53 and connected, through the aid of diametrically opposed pins 56, to arms 51. The arms 51 are supported by a slidable bar 58, the latter being slidably supported on an adjacent wall of a bracket or frame 59. A spring pressed plunger 80 mounted on the bracket 59 is manually actuable, through a head member 6|, to withdraw an end 62 from an aperture 63 in the bar 58 to free the bar for actuation of the clutch member 53, the end 62 when disposed in the aperture 83 causing the bar to hold the clutch member 53 in operative engagement with its companion member 41.

The means for supporting the upper rolls 28 and their respective gears 34, consists of individual shafts 85 upon which the upper rolls are mounted. Each shaft 65 is supported by a downwardly projecting bracket 65 of a pivotal arm 81 pivotally mounted on a common shaft or pin 68, the ends of which are disposedin small brackets 89 supported by the main bracket 58. The free end of each pivot arm has a handle portion 10 for use in manually moving each arm about its pivot to raise its respective upper roll out of engagement with the associated lower roll for the feeding of a strand 1| between the pairs of rolls. A spring 13 is provided for each pivot arm 61, the lower end of each spring being connected to an angle member 14 fixed to the table l2 while the upper end of each spring is connected to its respective adjusting screw 15. The adjusting screws extend through notches in horizontally projecting portions 16 of the pivot arms and receive wing nuts 18, which rest upon their projections or upon washers disposed upon the projections, for adjustment to vary the force of their respective springs and thus vary the force applied in moving each upper roll toward its respective lower roll.

In preparing the apparatus for operation, steam is applied to the chamber I5 to condition the material l1, causing it to be in a molten state. Additional material of the same chosen type may be supplied to the tank at a rate capable of maintaining a desired level of the material in the tank, this additional material being supplied in any conventional manner (not shown). The strands 1| to be coated by the material are then threaded through their respective dies, namely the cooperating recesses 21 and 30 of their respective rolls. This threading operation is made possible by manually moving the pivot arms 61 about their shaft 68 through the aid of the handles 10, to position the upper rolls desired distances from their lower rolls so that the strands may be placed in the recesses 21 of the lower rolls, after which the pivot arms may be moved to lower the upper rolls in place. If desired, supporting hooks or other devices may be employed to hold the pivot arms in their upper or threading positions.

The rolls may then be set in operation by causing interengagement of the clutch members to operatively connect the rolls 24 and 28, their gears 25 and 34, the shaft 28, the sprocket wheel 48, the chain 49 and the sprocket Wheel 46 to the power means, namely the unit 43. At the same time or in advance thereof, the strands 1| are advanced in the direction of the arrow (Fig. 1) at a linear speed faster than the surface speed of the respective rolls. The ratio of these speeds depends upon the nature of the material I1, the structure of the strand and the condition of the coating of the material on the strand desired. For illustration, let it be assumed that the strands are electrical conductors with insulating coverings formed of a braided, knitted or served textile and it is desirable that the coating material H be not only uniformly applied to the strand but partially embedded in the textile covering forming a part of the strand.

The nature of the material l1 and the contours of the grooves in the lower rolls 24 are such that during rotation of the latter a definite quantity of the material, as indicated at 80, will be carried upwardly around the strands to the tongue portions of the upper rolls. This material carried by the lower rolls fills the grooves 28 as well as the recesses 21, and is carried to points where it completely surrounds the strands and is controlled by the cooperationof the respective grooves and tongue portions. The action of the rolls in each pair is such that a constant supply of material is disposed about the strand passing therethrough, this supply of material being forced toward the strand through the cooperation of the interfitting groove and tongue portions of the rolls to cause the material to impregnate the strand while at the same time the recesses 21 and 30 cooperate to form a constantly moving die with a fixed aperture to control the'thickness of the coating of the material on the strand. This may be called a "rolling-in action produced not only by the die portions, namely the recesses 21 and 30, but the cooperation of the portions 29 and grooves 26 to apply a rolling force on the material toward the strand.

The rotation of the rolls in each pair at slower circumferential speeds than the linear speeds of the respective strands results in the forming of an axially unifbrm coating of th material by the rolling-in action between the rolling dies and the strands. Furthermore, the contours of the lower rolls are such that they will pick up a large amount of the material which is consumed by the strands due to the difference in speed of travel between the strands and their respective rolls. The supplying of the material to the strands at substantially the rate at which the material is consumed thereby, eliminates the kneading of the coating material which would tend to render the material stifl. and lumpy and possibly cause lumps to be, formed on the particles in the material on the rolls.

relationship of these associated surfaces. eliminates surface tension or cohesive force between the rolls and also eliminates the deposit or accumulation of material on the rolls. The rolls are thus kept clean and there is no periodically formed mass allowed to accumulate and become deposit on the strands. The rolls in each pair may, therefore, not only be called applicator rolls but finishing rolls as well as rolls which are self-cleaning. In this manner the die formed by the cooperating recesses 21 and 30 will be maintained clean at all times, to cause uniform application of the material to the strand, and will thus not be fouled by spent compound, grit, lint or other extraneous matters, as such are not allowed to accumulate on the rolls. Should there be any lumps present in the matter picked up by one of the lower rolls, the action of the rolls will force such a lump away' from the strand until the lump is eventually dropped back into the tank. This occasion should not occur, as

the materlalin the tank would normally be free of such lumps. The forming of lumps during the operation of the device is eliminated due to the prevention of accumulation of matter or The bevelled portions 3| and 32 of the rolls also assist in the freeing of such lumps from the rolls should they be present.

The embodiment of the invention herein disclosed is merely illustrative and may be modified and widely departed from in many ways without departing from the spirit and scope of the invention as pointed out in and limited solely by the appended claims.

What is claimed is:

1. In an apparatus for applying a coating of a viscous material to a strand, a container for retaining a supply of such a coating material, a

lower roll disposed so as to be partially immersed in the coating material held in the container and having formed therein an annular groove provided with an annular die-forming recess formed in a wall thereof, an upper roll having formed thereon an annular tongue portion entering the annular groove in the lower roll and having an annular die-forming recess formed therein, said recesses cooperating with each other to form a die having a predetermined configuration to control the quantity of coating material applied to a strand passing through the die, means for advancing a strand longitudinally through the die, and means for rotating the rolls to cause the groove in the lower roll to carry coating material from the container to the strand and to cooperate with the tongue portion in the upper roll to force the coating material toward the strand passing through the die.

2. An apparatus for coating a textile covered strand, comprising a container for a supply of viscous coating material, a lower roll disposed partially in the coating material, said roll having formed therein an annular peripheral groove provided with an annular die-forming recess formed in a wall thereof, an upper roll having formed thereon an annular peripheral tongue portion disposed in the said groove and having an annular die forming recess formed therein, said recesses cooperating with each other to form a die having a predetermined configuration to control the quantity of the coating material applied to a textile covered strand passing through the die, the groove and tongue portion being adapted to maintain alignment of the die-forming recesses during relative rotational movement of the rolls, means for advancing a textile covered strand longitudinally through the die, and means for rotating the rolls to cause the groove in the lower roll to feed the coating material from the container to the strand and to cooperate with the tongue portion in the upper roll to force the coating material toward the strand passing through the die.

3. A strand coating apparatus comprising a container for a supply of coating material, a lower roll disposed partially in the coating material and having formed therein an annular peripheral groove with an annular die-forming recess in a wall thereof, an upper roll provided with an annular tongue portion disposed in the said groove and having an annular die-forming recess therein cooperating with the recess of the lower roll to form a die having a predetermined configuration to control the quantity of the coating material applied to a strand passing therethrough, the side walls of the groove and the tongue'portion being parallel to maintain alignment of the recesses during relative movement of the rolls, and means for rotating the rolls to cause the groove to feed the coating material to a strand passing through the die and to cooperate with the tongue portion to force the coating material toward the strand.

4. In an apparatus for applying a viscous coating to a textile covered strand, a container for retaining a supply of such a coating material, a lower roll disposed so as to be partially, immersed in the coating material held in the container and having a peripheral groove of substantially rectangular cross section with an annular recess formed in the inner wall thereof, an upper roll with a peripheral tongue portion having an annular recess formed in the periphery thereof, said tongue portion conforming in cross section to the groove and cooperating closely therewith to maintain alignment of the recesses in the groove and tongue portion, and means for rotating the rolls to cause the groove to feed the coating material to a textile covered strand passing therebetween through the opening formed by the recesses and to cooperate with the tongue portion to force the coating material toward the strand and thereby impregnate the textile covering on the strand.

5. A strand coating apparatus comprising complementary interfitting rolls, one roll having an annular peripheral groove of substantially rectangular cross section with an annular recess formed in the bottom wall thereof, the other roll having an annular peripheral tongue portion of substantially rectangular contour so positioned as to substantially close the groove at positions of engagement, said tongue portion having an annular recess formed therein coopcrating with the recess of the groove to form a die having a predetermined configuration, a container to position a supply of coating material at such a level that one of the rolls is partially disposed therein, and means for rotating the rolls to cause the coating material to be fed to a textile covered strand passing therebetween by the roll disposed in the coating material and to cause cooperation of the groove and the tongue portions as well as the recesses to force the coating material toward the strand and thereby impregnate the covering on the strand, edges of the groove and the tongue portions being beveled to provide passageways for the escape periphery, which recesses cooperate to form a circular die having a diameter substantially greater than that of a strand to be advanced therethrough, a container to hold a supply of such a coating material at such a level that the grooved roll is partially immersed therein, and means for rotating the rolls to cause the groove to feed the coating material to a textile covered strand advancing therebetween and to cooperate with the tongue portion to force the coating material toward the strand and through the die, whereby the textile covering on the strand is thoroughly impregnated and uniformly coated with the coating material.

7. An apparatus for applying a viscous coating material to a textile covered strand, which comprises complementary rolls provided, respectively, with closely interfitting peripheral tongue and groove portions each having an annular recess formed in its periphery, which recesses cooperate with one another to form a die having a diameter substantially greater than that of a strand to be advanced therethrough,

2,823,487 7 means for advancing a textile covered strand longitudinally through the die, a container to hold a supply of a viscous coating material at such a level that one 01' the rolls is partially immersed in the coating material, and means for rotating the rolls at such a speed that the surfaces forming the die have the same linear speed and their linear speed is slower than that of a coated strand advancing therebetween to cause theviscous coating material to be fed by the roll immersed in the coating material to a textile covered strand passing between the rolls and to cause the die formed by the recesses to effect a rolling-in action upon the viscous coating applied to the strand, whereby the textile covering on the strand is thoroughly impregnated and uniformly coated with the coating material.

8. A strand coating apparatus comprising complementary rolls having, respectively, interfitting tongue and groove portions, a container to position a supply of material with the grooved roll partially disposed therein, means to cause rotation of the rolls relative to an advancing strand at a surface speed slower than the linear speed 01' the strand to cause the groove to feed the material to the strand and cooperate with the tongue portion to force the material toward the strand, the groove being of sufllcient size to feed the material at a rate equal to the rate of consumption of the material by the strand.

VDICENT A. RAYBURN. 

